Super absorbent thermochromic resin and preparation method thereof

ABSTRACT

A super absorbent thermochromic resin and a preparation method thereof are disclosed. The resin comprises the following components by weight percent: 30-60% of a monomer, 0.01-0.5% of an initiator, 0.01-4% of a dispersant, 0.01-5% of a cross-linking agent, 0-20% of a diluent, 0.5-2% of an auxiliary, 0.1-10% of a thermochromic pigment, and the balance of water. Compared with the prior art, the super absorbent thermochromic resin prepared by the present invention can effectively indicate the temperature changes of the resin in a drying state and a water absorption state through color changes. The reaction finishes in 6-10 min, with a simple process, smooth polymerization, short reaction time and high productivity. The super absorbent thermochromic resin has a good stability and can be widely applied to the medical industry and daily use articles industry.

CROSS REFERENCE OF RELATED APPLICATION

This is a U.S. National Stage under 35 U.S.C 371 of the InternationalApplication PCT/CN2017/082344, filed Apr. 28, 2017, which claimspriority under 35 U.S.C. 119(a-d) to CN 201610282041.3, filed Apr. 29,2016.

BACKGROUND OF THE PRESENT INVENTION Field of Invention

The present invention belongs to the technical field of functionalpolymer materials and relates to a thermochromic water-absorbent resinpolymer and a preparation method thereof.

Description of Related Arts

As a new kind of polymer material, super absorbent resin can absorbwater ten to thousands of times more than its mass, and has a good waterretention capacity under pressure or heat conditions. The superabsorbent resin after water absorption has rubber-like elasticity andgood thermal storage performance, and is highly safe and nontoxic. Inaddition, it is widely used in medicine, physical health, rehabilitationand other fields.

There is little discussion on the thermochromic water-absorbent resin inthe current literature, and the conventional water-absorbent resinproducts available on the market have no thermochromic function.Thermochromic water-absorbent resin, based on the originalwater-absorbent resin, has a new function of indicating temperaturechanges through color changes, so as to indicate safe use to users withsuitable thermochromic function and increase the interest of theproducts, thereby improving the safe and enjoyable experience of theproducts.

The conventional water-absorbent resin products on the market have nothermochromic function. The reason is that the thermochromic material isunstable and easy to agglomerate in polymerization reaction systems, orthe thermochromic function loses due to initiator and high temperature.The above-mentioned problems cannot be solved, even though conventionalthermochromic microcapsules are used. Therefore, it is difficult toprepare thermochromic water-absorbent resin.

SUMMARY OF THE PRESENT INVENTION

In view of the above technical defects, an object of the presentinvention is to provide a super absorbent thermochromic resin and apreparation method thereof.

The object of the present invention is realized by means of thefollowing technical solution:

In a first aspect, the present invention provides a super absorbentthermochromic resin, which comprises following components by weightpercent:

a monomer  30-60%; an initiator 0.01-0.5%;  a dispersant 0.01-4%; across-linking agent 0.01-5%; a diluent  0-20%; a thermochromic pigment0.1-10%;

and a balance of water.

The conventional water-absorbent resin only has a high water absorptionfunction. By adding a thermochromic material to improve the formula, anew water-absorbent resin with the function of thermochromism isprepared after thorough mixing and reaction, thereby reminding users oftemperature changes to the new water-absorbent resin and preventing theusers from being burned or frostbite.

Further preferably, the thermochromic water-absorbent resin compositioncomprises the following components by weight percent:

the monomer  40-55%; the initiator 0.05-0.3%;  the dispersant 0.4-3.5%;the cross-linking agent 0.1-4.5%; the diluent 0.4-15.8%;  thethermochromic pigment  4-7.5%;

and the balance of water.

The above percentages refer to the weight percentage of specificcomponents in the obtained super absorbent thermochromic resin.

The super absorbent thermochromic resin prepared using conventionalmethods shows poor discoloration. By adjusting the proportion of eachraw material in the formula, the super absorbent thermochromic resinafter water absorption shows obvious color changing upon temperaturerise or cooling.

Further preferably, the super absorbent thermochromic resin comprisesthe following components by weight percent:

the monomer  40-55%; the initiator 0.05-0.3%;  the dispersant 0.4-3.5%;the cross-linking agent 0.1-4.5%; the diluent 0.4-15.8%;  thethermochromic pigment  4-7.5%; the auxiliary  0.5-2%;

and the balance of water.

The addition of an auxiliary in the process of synthesizingwater-absorbent resin can overcome the problem of poor ductility andfragility of the conventional water-absorbent resin, and greatly improvethe user's comfort.

Preferably, the water is deionized water or distilled water.

Preferably, the monomer comprises an acrylic monomer, which isspecifically selected from a group consisting of acrylamide, acrylate,acrylic acid, vinyl acetate, N-vinyl pyrrolidone, acrylonitrile,methacrylic acid, methacrylate and an acrylate system as shown in thefollowing structural formula I.

wherein, R1 is C1-C5, R2 is H or Cl.

More preferably, the monomer is one or two of acrylate and acrylamide;both are the acrylic monomer with a good hydrophilicity; copolymersformed by the two have good mechanical properties after waterabsorption, and is beneficial to dispersion of the thermochromicpigment.

Preferably, the initiator is selected from a group consisting ofazobisisobutyronitrile (AIBN), cerium salts, persulfate, apersulfate-NaHSO₃ system and a hydrogen peroxide-ascorbic acid system.

More preferably, the initiator is selected from persulfate; further, thedispersant is Na₂S₂O₈; a decomposition product is Na₂SO₄, which exerts alowest impact on the thermochromic water-absorbent resin, greatly speedsup the reaction and obtains the product.

Preferably, the dispersant is selected from a group consisting of Span60, Tween 80, Tween 85 and nonylphenol polyoxyethylene ether-10 (OP-10).Selecting proper dispersant may allow uniform dispersion of thethermochromic pigment free of agglomeration and make discoloration ofthe product more obvious.

Preferably, the cross-linking agent is selected from a group consistingof ethylene glycol dimethacrylate, diethylene glycol dimethacrylate,allyl methacrylate, 1,1,1-trimethylolpropane acrylate, N,N′-methylenediacrylamide, triallylamine and tetraallyloxyethane.

Preferably, the diluent is mainly polyhydric alcohol;

More preferably, the diluent is selected from a group consisting ofglycerol, pentaerythritol, trimethylol ethane, propylene glycol anddiethylene glycol.

Preferably, the auxiliary is at least one of inorganic salts and organiccompounds; the inorganic salts comprise one or more of sodiumtripolyphosphate, zinc sulfate, potassium aluminum sulfate, sodiumchloride and potassium chloride, and the organic compounds comprise atleast one of polyethylene glycol (200-6000) and polyethylene glycolglyceride. The addition of the auxiliary effectively improves theductility and hardness of the product.

Preferably, the thermochromic pigment is a water dispersion typereversible thermochromic microcapsule pigment/dye. The colorclassification of dye is as follows: blue, orange, red, green, carmineand black; a temperature for discoloration ranges between −15° C. and70° C.; a common temperature is −5° C., 0° C., 5° C., 15° C., 31° C.,43° C. and 55° C. High, medium and low-temperature segmenteddiscoloration of water-absorbent resin through mutual collocation orcollocation with other background pigments can be realized. For example:two-segmented discoloration effect can be realized by mixingthermochromic dye with a temperature below 0° C. and thermochromic dyewith a temperature above 50° C., while three-segmented discolorationeffect can be realized by mixing thermochromic dye with a temperaturebelow 0° C., thermochromic dye with a temperature above 31° C. andthermochromic dye with a temperature above 50° C.

In a second aspect, the present invention provides a preparation methodof a super absorbent thermochromic resin, wherein the preparation methodcomprises following steps of: adding a thermochromic pigment, adispersant, a cross-linking agent and a diluent to a monomer and mixinguniformly; adjusting a pH value, and adding an initiator; mixinguniformly to form a reaction system, controlling a reaction temperatureto perform reaction, and obtaining the super absorbent thermochromicresin.

Preferably, the present invention preliminarily mixes and disperses thethermochromic pigment and the dispersant, and then transfers it into themonomer to uniformly mix them, effectively solving the phenomenon ofinternal agglomeration of pigment after the super absorbentthermochromic resin is produced.

Preferably, the mode of mixing uniformly includes stirring.

Preferably, the step of adjusting the pH value is specifically adding analkali solution.

Preferably, the pH value after being adjusted is 5-9.

Further preferably, the pH value after being adjusted is 6-8. Due to theelectrical properties of the thermochromic dye, a too high or too low pHvalue will cause the precipitation and agglomeration of thethermochromic pigment. By adjusting the pH value, the agglomeration ofthe thermochromic pigment can be avoided.

Preferably, the reaction temperature is controlled at 55-90° C.

Further preferably, the reaction temperature is controlled at 65-85° C.The microcapsule structure of the thermochromic pigment will be damageddue to a too high reaction temperature, so that the pigment fades orloses the discoloration effect. By adjusting the reaction temperature,the loss of discoloration caused by high temperature can be avoided. Thetemperature indication range of the polymer of this invention variesdepending on the thermochromic pigment. The commonly adopted usetemperature of the thermochromic water-absorbent resin is −15-70° C.,preferably, the temperature indication range is −10-10° C., 30-35° C.and 50-55° C.; specifically: the temperature of below −5° C. easilycauses frostbite, and the temperature of above 50° C. easily causesburns of a sensitive person, therefore, the temperatures within therange of −10-10° C. and 50-55° C. are reminder alerts.

Compared with the prior art, the present invention has the followingbeneficial effects:

1. In the present invention, by adding water dispersion type reversiblethermochromic microcapsule pigment/dye to the original monomer andimproving the addition proportion of each raw material in the originalformula, a super absorbent thermochromic resin is obtained. Before andafter water absorption, the resin has a significant color change, whichpreventing users from being burned at high temperatures or frostbite atlow temperatures, and has a high water absorption function.

2. In the present invention, selecting a proper dispersant and addingthermochromic pigment and dispersant mixed in the experimental steps tothe monomer effectively solves the problem that the thermochromicpigment is unstable and easy to agglomerate. As a result, the product,namely super absorbent thermochromic resin, is significant inthermochromism and achieves a good indication effect.

3. In the present invention, by changing the reaction temperature forproduction, it is possible to find a balance between the reactiontemperature and the temperature affecting the thermochromic pigment,thereby effectively preventing thermochromic pigment from loss ofthermochromism caused by high temperature and keeping the productionnormal.

4. In the present invention, by adding the initiator, it is possible toshorten the reaction time to only 6-10 min, and it is not necessary tofill with nitrogen, thereby overcoming such problems as low reactionrate and yield.

5. In the present invention, the added auxiliary can change the functionof the polymerization bond in the polymerization of the monomer, and thetemperature-sensitive phase transition microcapsules are stably presentin the polymer, and the agglomerate structure of the polymer can bechanged to increase the ductility and hardness of the product.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is described in detail as follows with referenceto specific embodiments. The following embodiments will help providefurther understanding of the present invention for those skilled in theart, and not in any way limit the present invention. It shall be notedthat several variants and improvements can be made without departingfrom concept of the present invention for ordinary persons skilled inthe art. All these fall within the protection scope of the presentinvention.

Embodiment 1

The embodiment provides a super absorbent thermochromic resin and apreparation method thereof, wherein components and contents involved areshown in Table 1; and the preparation method comprises the followingsteps of:

adding 30 g of acrylic acid to water; adjusting the solution with NaOHuntil pH=6.5; feeding nitrogen into a reactor; adding 0.4 g of Tween 60,0.2 g of ethylene glycol dimethacrylate and 4 g of thermochromic dye(Guangdong New Prismatic Enterprise Co., Ltd., color changes from blueto colorless at −5° C. and the process is reversible upon temperaturedrop); stirring, keeping feeding nitrogen for 2 hours, and then adding0.02 g of Na₂S₂O₈ to a mixed liquor; performing heat preservation on anobtained reaction system (a total of 100 g) at 80° C. for 10 minutes toperform a polymerization reaction; cooling to room temperature, and thenusing a scraper for removing a gel from the reactor; drying the gel inan oven at 70° C.; and grinding the gel.

Embodiment 2

The embodiment provides a super absorbent thermochromic resin and apreparation method thereof, wherein components and contents involved areshown in Table 1; and the preparation method comprises the followingsteps of:

stirring and mixing 38 g of acrylic acid, 2 g of acrylonitrile, 0.5 g ofOP-10 and 2 g of pentaerythritol with deionized water; adding 20 g of 9%NaOH for regulating the system pH to 5.5; adding 0.5 g of diethyleneglycol dimethacrylate and 4 g of thermochromic dye (Guangzhou KingcaiPigment Co., Ltd., color changes from yellow to colorless at 30° C. andthe process is reversible upon temperature drop); stirring, feeding N₂for 2 hours, and then adding 0.03 g of AIBN to the mixture; stirringuniformly (the reaction system totals 100 g), and then using anindustrial white oil with a temperature of 80° C. as a continuous phaseand using the mixture as a dispersed phase for suspensionpolymerization; stirring for 15 minutes, and then filtering the whiteoil to obtain resin particles; using tetrahydrofuran to wash away thewhite oil on the surfaces of the resin particles; and drying in a vacuumdrying oven at 80° C. to obtain water-absorbent resin microbeads.

Embodiment 3

The embodiment provides a super absorbent thermochromic resin and apreparation method thereof, wherein components and contents involved areshown in Table 1; and the preparation method comprises the followingsteps of:

adding 30.5 g of acrylic acid to 15 g of 9% NaOH solution to obtain amixture a; adding 17 g of acrylamide, 2.5 g of N-vinyl pyrrolidone, 3 gof glycerol, 4 g of thermochromic pigment (Dongguan BiansefengIndustrial Investment Co., Ltd., color changes from green to yellowgreen at 45° C. and the process is reversible upon temperature drop),0.7 g of triallylamine, 0.3 g of Tween 80, 0.4 g of OP-10 to deionizedwater to obtain a mixture b; mixing the mixture a and mixture b andstirring uniformly to obtain a mixture c; feeding N₂ into the mixture cfor 2 hours, and then adding 1 g of 2% (by mass) ceric ammonium nitratesolution; mixing uniformly (the reaction system totals 100 g), and thenheating for 10 minutes in 80° C. water bath; after cooling, using ascraper for removing a gel from the reaction system; placing in an ovenat 80° C. for 10 minutes, and then crushing to obtain the thermochromicwater-absorbent resin powder.

Embodiment 4

The embodiment provides a super absorbent thermochromic resin and apreparation method thereof, wherein components and contents involved areshown in Table 1; and the preparation method comprises the followingsteps of:

adding 40 g of acrylic acid to 30 g of 5% NaOH solution, adjusting thesolution until pH=4, and then adding 17 g of acrylamide, 3 g of vinylacetate, 4 g of thermochromic pigment (Dongguan Biansefeng IndustrialInvestment Co., Ltd., color changes from red to colorless at 55° C. andthe process is reversible upon temperature drop), 4 g of glycerol, 0.6 gof Tween 60, 0.6 g of OP-10 and 0.78 g of allyl methacrylate;continuously stirring and feeding N₂; after 2 hours, adding 0.01 mL of30% hydrogen peroxide and 0.01 g of L-ascorbic acid, and using anindustrial white oil as a continuous phase and using the above-mentionedmixture (a total of 100 g) as a dispersed phase for performingsuspension polymerization at 75° C.; filtering after 10 minutes, andwashing the filtrate with petroleum ether, and drying at 75° C. toobtain the thermochromic water-absorbent resin (water contained in theNaOH solution).

Embodiment 5

The embodiment provides a super absorbent thermochromic resin and apreparation method thereof, wherein components and contents involved areshown in Table 1; and the preparation method comprises the followingsteps of:

adding 30 g of acrylic acid to 25 g of 5% NaOH solution, adjusting thesolution until pH=6, and then adding 15 g of acrylamide, 4 g ofthermochromic pigment (Taiwan New Prismatic Enterprise Co., Ltd., colorchanges from dark purple to light purple to red and then colorless at 0°C., 30° C. and 55° C.), 0.4 g of Span 60, 0.6 g of OP-10 and 2 g ofpolyethylene glycol and 0.5 g ethylene glycol dimethacrylate;continuously stirring and feeding N₂; after 2 hours, adding 0.02 g ofNa₂S₂O₈ to, and using an industrial white oil as a continuous phase andusing the above-mentioned mixture (a total of 100 g) as a dispersedphase for performing suspension polymerization at 75° C.; filteringafter 10 minutes, and washing the filtrate with petroleum ether mixedwith tetrahydrofuran (1:1), and drying at 75° C. to obtain thethermochromic water-absorbent resin (water contained in the NaOHsolution).

Embodiment 6

The embodiment provides a super absorbent thermochromic resin and apreparation method thereof, wherein components and contents involved areshown in Table 1; and the preparation method comprises the followingsteps of:

mixing 4 g of thermochromic dye (Guangzhou Kingcai Pigment Co., Ltd.,color changes from bright orange to orange red to red and then colorlessat −5° C., 30° C. and 55° C.) with 0.3 g of Span first; mixing andstirring 35 g of acrylic acid, 0.4 g of Tween 85, 5 g of propyleneglycol and deionized water, adding 22 g of 10% NaOH to adjust the systemuntil pH=5.5, adding 1.3 g of polyethylene glycol glyceride, 0.9 g ofN′N-methylenebisacrylamide and stirring them, feeding N₂ for 2 hours,and then adding 0.01 g of potassium persulfate to the mixture; stirringuniformly (the reaction system totals 100 g), and then using anindustrial white oil with a temperature of 80° C. as a continuous phaseand using the mixture as a dispersed phase for suspensionpolymerization; stirring for 15 minutes, and then filtering the whiteoil to obtain resin particles; using tetrahydrofuran to wash away thewhite oil on the surfaces of the resin particles; and drying at 80° C.to obtain spherical water-absorbent resin.

Embodiment 7

Embodiment 7 provides a thermochromic water-absorbent resin compositionand a preparation method thereof, wherein components and contentsinvolved are shown in Table 1; and the preparation method is basicallythe same as that of Embodiment 2, with the difference being the additionof 0.8 g of zinc sulfate as the auxiliary.

Embodiment 8

Embodiment 8 provides a super absorbent thermochromic resin and apreparation method thereof, wherein components and contents involved areshown in Table 1; and the preparation method is basically the same asthat of Embodiment 3, with the difference being the addition of 1.3 g ofsodium chloride as the auxiliary and 4 g of thermochromic dye (DongguanBiansefeng Industrial Investment Co., Ltd., color changes from purple toblue to red and then colorless at 0° C., 30° C. and 55° C.).

TABLE 1 Components and Contents Involved in Embodiments 1-8 EmbodimentEmbodiment Embodiment Embodiment Embodiment Embodiment EmbodimentEmbodiment 1 2 3 4 5 6 7 8 Monomer 30% 38% 30.5% 40% 30% 35% 38% 30.5%acrylic acid acrylic acid acrylic acid acrylic acid acrylic acid acrylicacid acrylic acid acrylic acid 2% 17% 17% 15% 2% 17% acrylonitrileacrylamide acrylamide acrylamide acrylonitrile acrylamide 2.5% N- 3%vinyl 2.5% N- vinyl acetate vinyl pyrrolidone pyrrolidone Initiator0.02% 0.03% 0.02% 0.02% 0.02% 0.01% 0.03% 0.02% Na₂S₂O₈ AIBN cerichydrogen Na₂S₂O₈ potassium AIBN ceric ammonium peroxide- persulfateammonium nitrate ascorbic nitrate acid Diluent 0 2% 3% 4% 0 5% 2% 3%pentaerythritol propylene glycerol propylene pentaerythritol propyleneglycol glycol glycol Dispersant 0.4% 0.5% 0.3% 0.6% 0.6% 0.3% 0.5% 0.3%Tween 60 OP-10 Tween 80 OP-10 OP-10 Span 60 OP-10 Tween 80 0.4% 0.6%0.4% 0.4% 0.4% OP-10 Tween 60 Span 60 Tween 85 OP-10 Cross- 0.2% 0.5%0.7% 0.78% 0.5% 0.9% 0.5% 0.7% linking ethylene diethylene triallylamineallyl ethylene N′N- diethylene triallylamine agent glycol glycolmethacrylate glycol methylen glycol dimethacrylate dimethacrylatedimethacrylate ebisacrylamide dimethacrylate Auxiliary 2% 1.3% 0.8% 1.3%polyethylene polyethylene zinc sodium glycol glycol sulfate chlorideglyceride Thermochromic 4% 4% 4% 4% 4% 4% 4% 4% pigment (Guangdong(Guangzhou (Dongguan (Dongguan (Taiwan (Guangzhou (Guangzhou (DongguanNew Kingcai Biansefeng Biansefeng New Kingcai Kingcai BiansefengPrismatic Pigment Industrial Industrial Prismatic Pigment PigmentIndustrial Enterprise Co., Ltd., Investment Investment Enterprise Co.,Ltd., Co., Ltd., Investment Co., Ltd., color Co., Ltd., Co., Ltd., Co.,Ltd., color color Co., Ltd., color changes color color color changeschanges color changes from changes changes changes from from changesfrom yellow to from from red from bright yellow to from blue tocolorless green to to dark orange to colorless purple to colorless at30° C. yellow colorless purple to orange at 30° C.) blue to at −5° C.and the green at at 55° C. light red to red and and the process is 45°C. and the purple to red and then process is reversible and the processis red and then colorless reversible upon process is reversible thencolorless at 0° C., upon temperature reversible upon colorless at −5°C., 30° C. temperature drop) upon temperature at 0° C., 30° C. and drop)temperature drop 30° C. and 55° C.) drop) and 55° C.) 55° C.) DeionizedBalance Balance Balance Balance Balance Balance Balance Balance water(distilled water)

See Table 2 for the performance test results of compositions inEmbodiments 1-4:

TABLE 2 Performance Test of Compositions Obtained in Embodiments 1-4Embodiment Embodiment Embodiment Embodiment Embodiment EmbodimentEmbodiment Embodiment 1 2 3 4 5 6 7 8 Color Colorless Yellow Green RedLight Orange Yellow Blue uniformity at 25° C. at 25° C. at 25° C. at 25°C. purple red at 25° C. at 25° C. after water at 25° C. at 25° C.absorption of resin The Blue Yellow Green Red Dark Bright Yellow Purplethermochromic when the when the when the when the purple orange when thewhen the performance ambient ambient ambient ambient when the when theambient ambient after water temperature temperature temperaturetemperature ambient ambient temperature temperature absorption is isbelow is below is below temperature temperature is below is below ofresin below −5° C., 30° C., 45° C., 55° C., is below is 30° C., 0° C.,colorless colorless yellow colorless 0° C., below −5° C., colorless bluewhen the when the green when the light orange when the when the ambientambient when the ambient purple red ambient ambient temperaturetemperature ambient temperature when the when the temperaturetemperature is is above temperature is above ambient ambient is above isabove above −5° C. 30° C. is above 55° C. temperature temperature 30° C.0° C. and (not (not 45° C. (not is above is (not below exceedingexceeding (not exceeding 0° C. and above −5° C. exceeding 30° C., 90°C.) 90° C.) exceeding 90° C.) below and below 90° C.) red 90° C.) 30°C., 30° C., when the red red ambient when the when the temperatureambient ambient is above temperature temperature 30° C. is above isabove and 30° C. 30° C. below and below and below 55° C. 55° C. 55° C.and and and colorless colorless colorless when the when the when theambient ambient ambient temperature temperature temperature is above isabove is above 55° C. 55° C. 55° C. (not (not (not exceeding exceedingexceeding 90° C.) 90° C.) 90° C.) The No No No No No No No Nothermochromic significant significant significant significantsignificant significant significant significant performance changeschanges changes changes changes changes changes changes after in the inthe in the in the in the in the in the in the naturally thermochromicthermochromic thermochromic thermochromic thermochromic thermochromicthermochromic thermochromic aging performance performance performanceperformance performance performance performance performance for 100hours at 25° C. after water absorption of resin The No No No No No No NoNo thermochromic significant significant significant significantsignificant significant significant significant performance changeschanges changes changes changes changes changes changes after in the inthe in the in the in the in the in the in the naturally thermochromicthermochromic thermochromic thermochromic thermochromic thermochromicthermochromic thermochromic aging performance performance performanceperformance performance performance performance performance for 200hours at 25° C. after water absorption of resin The No No No No No No NoNo thermochromic significant significant significant significantsignificant significant significant significant performance changeschanges changes changes changes changes changes changes after in the inthe in the in the in the in the in the in the naturally thermochromicthermochromic thermochromic thermochromic thermochromic thermochromicthermochromic thermochromic aging performance performance performanceperformance performance performance performance performance for 300hours at 25° C. after water absorption of resin Compressive25N/particle, 27N/particle, 27N/particle, 33N/particle, 45N/particle,42N/particle, 52N/particle, 44N/particle, strength high in high in highin high in very very very very of the strength strength strengthstrength high in high in high in high in product and not and not and notand not strength strength strength strength (detection easy to easy toeasy to easy to and not and not and not and not by a be crushed becrushed be crushed be crushed easy to easy to easy to easy to particlebe crushed be crushed be crushed be crushed strength tester)

Comparative Examples 1-6

The comparative examples 1-6 belong to Embodiment 2, and the preparationmethod is same as Embodiment 2; see Table 3 for the comparison:

TABLE 3 Components and Contents Involved in the Comparative Examples 1-6Comparative Comparative Comparative Comparative Comparative Comparativeexample 1 example 2 example 3 example 4 example 5 example 6 Monomer 18%Same as Same as Same as Same as 10.5% acrylic acid Embodiment EmbodimentEmbodiment Embodiment acrylic acid 2% 2 2 2 8 12.5% N- acrylonitrilevinyl pyrrolidone Initiator Same as 0.3% Same as Same as Same as 0.2%ceric Embodiment AIBN Embodiment Embodiment Embodiment ammonium 2 2 2 8nitrate Diluent Same as Same as Same as Same as 24% Same as EmbodimentEmbodiment Embodiment Embodiment glycerol Embodiment 2 2 2 2 8Dispersant Same as 0.5% Same as 5% Same as Same as Embodiment OP-10Embodiment OP-10 Embodiment Embodiment 2 2 8 8 Cross- Same as Same as0.005% 0% 0.005% Same as linking Embodiment Embodiment diethylene allylEmbodiment agent 2 2 glycol methacrylate 8 dimethacrylate Auxiliary Sameas Same as Embodiment Embodiment 8 8 Thermochromic Same as Same as 11%Same as Same as Same as pigment Embodiment Embodiment (GuangzhouEmbodiment Embodiment Embodiment 2 2 Kingcai 2 8 8 Pigment Co., Ltd.,color changes from yellow to colorless at 30° C. and the process isreversible upon temperature drop) Deionized Balance Balance BalanceBalance Balance Balance water (distilled water)

See Table 6 for the performance test results of compositions in thecomparative examples 1-4:

TABLE 4 Performance Test Results of Compositions in the ComparativeExamples 1-6 Comparative Comparative Comparative Comparative ComparativeComparative example 1 example 2 example 3 example 4 example 5 example 6Color Uneven Uniform Uneven Uneven Uneven Uneven uniformity color colorcolor color color color after water change absorption of resin TheYellow Yellow Yellow Yellow Purple Purple thermochromic when the whenthe when the when the when the when the performance ambient ambientambient ambient ambient ambient after water temperature temperaturetemperature temperature temperature temperature absorption is below isbelow is below is below is below is below of resin 30° C., 30° C., 30°C., 30° C., 0° C., blue 0° C., blue colorless colorless colorlesscolorless when the when the when the when the when the when the ambientambient ambient ambient ambient ambient temperature temperaturetemperature temperature temperature temperature is above is above isabove is above is above is above 0° C. and 0° C. and 30° C. (not 30° C.(not 30° C. (not 30° C. (not below below exceeding exceeding exceedingexceeding 30° C., red 30° C., red 90° C.) 90° C.) 90° C.) 90° C.) whenthe when the ambient ambient temperature temperature is above is above30° C. and 30° C. and below below 55° C. and 55° C. and colorlesscolorless when the when the ambient ambient temperature temperature isabove is above 55° C. (not 55° C. (not exceeding exceeding 90° C.) 90°C.) The No No No No No No thermochromic significant significantsignificant significant significant significant performance changeschanges changes changes changes changes after in the in the in the inthe in the in the naturally thermochromic thermochromic thermochromicthermochromic thermochromic thermochromic aging for performanceperformance performance performance performance performance 100 hours at25° C. after water absorption of resin The No No No No No Nothermochromic significant significant significant significantsignificant significant performance changes changes changes changeschanges changes after in the in the in the in the in the in thenaturally thermochromic thermochromic thermochromic thermochromicthermochromic thermochromic aging for performance performanceperformance performance performance performance 200 hours at 25° C.after water absorption of resin The No No No No No No thermochromicsignificant significant significant significant significant significantperformance changes changes changes changes changes changes after in thein the in the in the in the in the naturally thermochromic thermochromicthermochromic thermochromic thermochromic thermochromic aging forperformance performance performance performance performance performance300 hours at 25° C. after water absorption of resin Change in15N/particle; 13N/particle; 27N/particle; 11N/particle; 7N/particle;8N/particle; mechanical compared compared compared compared comparedcompared properties with the with the with the with the with the withthe of the embodiment, embodiment, embodiment, embodiment, embodiment,embodiment, product the the no the the the (detection compressivemechanical significant mechanical compressive mechanical by a strengthproperties changes properties strength properties particle of the ofproduct in the of product of the of product strength product is arereduced, mechanical are reduced, product is are reduced, tester) loweredand the properties and the lowered and the product is of the product isand the product is easily product pretty product is pretty broken easilyeasily easily broken broken. broken with water with water leakageleakage

Comparative Examples 7-8

The comparative examples 7 and 8 belong to Embodiment 2; the componentsand contents are the same as Embodiment 2, except that the preparationmethod is different:

The difference between the comparative example 7 and Embodiment 2 liesin: the initiation temperature is set as 95° C.; the heat release of thesystem is increased, and the reaction rate is accelerated. Thechromogenic performance of the formed gel is damaged, and the colorchange is not obvious.

The difference between the comparative example 8 and Embodiment 2 liesin: before using NaOH solution for regulating the system pH, themonomer, the stabilizer and thermochromic pigment are mixed. Thechromogenic performance of the prepared gel is damaged, and the colordistribution is uneven. There are agglomerates visible to the naked eye.

Specific embodiments of the present invention are described above. Itshall be understood that the present invention is not limited to theabove-mentioned specific embodiments, and those skilled in the art canmake different variants and modifications within the scope of theclaims, and it shall not affect the substance of the present invention.

1-12. (canceled)
 13. A super absorbent thermochromic resin, comprisingfollowing components by weight percent: a monomer  30-60%; an initiator0.01-0.5%;  a dispersant 0.01-4%; a cross-linking agent 0.01-5%; adiluent  0-20%; a thermochromic pigment 0.1-10%;

and a balance of water.
 14. The super absorbent thermochromic resinaccording to claim 13, wherein the thermochromic water-absorbent resincomposition comprises the following components by weight percent: themonomer  40-55%; the initiator 0.05-0.3%;  the dispersant 0.4-3.5%; thecross-linking agent 0.1-4.5%; the diluent 0.4-15.8%;  the thermochromicpigment  4-7.5%;

and the balance of water.
 15. The super absorbent thermochromic resinaccording to claim 13, wherein the thermochromic water-absorbent resincomposition comprises the following components by weight percent: themonomer  40-55%; the initiator 0.05-0.3%;  the dispersant 0.4-3.5%; thecross-linking agent 0.1-4.5%; the diluent 0.4-15.8%;  the thermochromicpigment  4-7.5%; the auxiliary  0.5-2%;

and the balance of water.
 16. The super absorbent thermochromic resinaccording to claim 14, wherein the thermochromic water-absorbent resincomposition comprises the following components by weight percent: themonomer  40-55%; the initiator 0.05-0.3%;  the dispersant 0.4-3.5%; thecross-linking agent 0.1-4.5%; the diluent 0.4-15.8%;  the thermochromicpigment  4-7.5%; the auxiliary  0.5-2%;

and the balance of water.
 17. The super absorbent thermochromic resinaccording to claim 13, wherein the monomer comprises an acrylic monomer;and the thermochromic pigment is a reversible thermochromic microcapsulepigment/dye of water dispersion type.
 18. The super absorbentthermochromic resin according to claim 14, wherein the monomer comprisesan acrylic monomer; and the thermochromic pigment is a reversiblethermochromic microcapsule pigment/dye of water dispersion type.
 19. Thesuper absorbent thermochromic resin according to claim 13, wherein theinitiator is selected from a group consisting of azobisisobutyronitrile,cerium salts, persulfate, a persulfate-NaHSO₃ system and a hydrogenperoxide-ascorbic acid system.
 20. The super absorbent thermochromicresin according to claim 14, wherein the initiator is selected from agroup consisting of azobisisobutyronitrile, cerium salts, persulfate, apersulfate-NaHSO₃ system and a hydrogen peroxide-ascorbic acid system.21. The super absorbent thermochromic resin according to claim 13,wherein the dispersant is selected from a group consisting of Span 60,Tween 80, Tween 85 and OP-10 (nonylphenol polyoxyethylene ether-10). 22.The super absorbent thermochromic resin according to claim 14, whereinthe dispersant is selected from a group consisting of Span 60, Tween 80,Tween 85 and OP-10.
 23. The super absorbent thermochromic resinaccording to claim 13, wherein the cross-linking agent is selected froma group consisting of ethylene glycol dimethacrylate, diethylene glycoldimethacrylate, allyl methacrylate, 1,1,1-trimethylolpropane acrylate,triallylamine, N,N′-methylene diacrylamide and tetraallyloxyethane. 24.The super absorbent thermochromic resin according to claim 14, whereinthe cross-linking agent is selected from a group consisting of ethyleneglycol dimethacrylate, diethylene glycol dimethacrylate, allylmethacrylate, 1,1,1-trimethylolpropane acrylate, triallylamine,N,N′-methylene diacrylamide and tetraallyloxyethane.
 25. The superabsorbent thermochromic resin according to claim 13, wherein the diluentis a polyhydric alcohol.
 26. The super absorbent thermochromic resinaccording to claim 14, wherein the diluent is a polyhydric alcohol. 27.The super absorbent thermochromic resin according to claim 13, whereinthe auxiliary is at least one of inorganic salts and organic compounds;the inorganic salts comprise one or more of sodium tripolyphosphate,zinc sulfate, potassium aluminum sulfate, sodium chloride and potassiumchloride, and the organic compounds comprise at least one ofpolyethylene glycol and polyethylene glycol glyceride.
 28. A preparationmethod of a super absorbent thermochromic resin, wherein the preparationmethod comprises following steps of: adding a thermochromic pigment, adispersant, a cross-linking agent, an auxiliary and a diluent to amonomer and mixing uniformly; adjusting a pH value, and adding aninitiator; mixing uniformly to form a reaction system, controlling areaction temperature, time and speed to perform reaction, and obtainingthe super absorbent thermochromic resin.
 29. The preparation method ofthe super absorbent thermochromic resin according to claim 28, whereinthe reaction comprises solution polymerization or inverse suspensionpolymerization.
 30. The preparation method of the super absorbentthermochromic resin according to claim 28, wherein the pH value afterbeing adjusted is 5-8; the reaction temperature is controlled between55-90° C.